see picture below, here
and here
and here.
This cancer is treated similarly to other sites within the oropharynx. NCCN Guidelines: for oropharynx cancer
here and recommended
radiation dose.)
read
review and here

(cancer
of the hard palate is much less common and can be found here.)

Data on right is from U Florida study below, showing local control of soft palate
cancer with radiation therapy treatment

Int J Radiat Oncol Biol Phys 2001 Jun 1;50(2):359-66

SOFT PALATE CANCER — Early stage soft palate cancers
may behave in a relatively indolent manner and remain in the
early stages. Most patients do not have palpable cervical lymph
nodes, but there is a significant correlation between tumor
thickness and nodal disease. In one study of 39 patients, for
example, none of the 24 lesions ≤2.86 mm were associated with
cervical adenopathy, while all of the 15 lesions ≥3.12 mm had
palpable adenopathy . Patients with thicker lesions also had a
worse prognosis.

Patients with early soft
palate cancer are usually treated with radiotherapy delivered as
external beam radiotherapy (EBRT), interstitial brachytherapy,
or both. The use of prophylactic neck irradiation or observation
remains controversial. The neck should be electively
treated if the risk of occult metastatic disease exceeds 15
percent, given the poor prognosis with observation in this
setting. If surgery is chosen for the primary tumor, then we
recommend elective surgical treatment of the neck since even
patients with early lesions and a negative neck are at risk for
lymph node metastases. If EBRT is chosen for the primary tumor,
the neck should be electively irradiated.

Radiotherapy — The
initial volume includes the entire soft palate and adjacent
pillars and the upper neck; EBRT is given using opposed lateral
fields. Some institutions have suggested that, for
well-lateralized lesions, elective nodal radiotherapy can be
confined to the ipsilateral neck. The boost volume can be
treated by EBRT, intraoral cone (performed prior to EBRT) or, in
selected cases, interstitial brachytherapy.

For T1 lesions, we administer 50 Gy
in 25 fractions by EBRT plus 16 Gy in eight fractions boost
by EBRT or 15 Gy in six fractions boost by intraoral cone.

Some centers advocate the use of
interstitial brachytherapy with iridium 192 in conjunction with
EBRT for small soft palate lesions since this spares the major
salivary glands and reduces the risk of xerostomia. The EBRT
dose is usually 50 Gy in 25 fractions, followed by a 15 to 30 Gy
single plane implant.

Results — External
beam radiotherapy produces local control in approximately 87 to
92 of T1 lesions and 70 to 75 percent of T2 lesions . The
five-year survival in one study of 75 patients was 83, 78, and
38 percent, respectively, with stage I, II, and III disease,
respectively.

Adverse sequelae including soft tissue
necrosis are uncommon, occurring in less than 10 percent of
patients. Severe complications, principally osteonecrosis of the
mandible requiring surgical resection, occur in less than 5
percent

Similar outcomes have been described in
patients with soft palate cancer treated with EBRT and
brachytherapy . Estimated five year values for disease-free and
overall survival have been 43 and 57 percent, respectively.

The duration of therapy may be important
with combination therapy. In one series of 370 patients with
soft palate and tonsillar carcinoma (two-thirds of whom had T1
or T2 disease), the total duration of irradiation and the delay
between external irradiation and brachytherapy were significant
prognostic factors for local control and overall survival . It
was suggested that the overall duration should not be more than
seven weeks: five weeks of external irradiation plus a delay of
12 to 15 days, but not more than 20 days, between external
therapy and brachytherapy. At five years, patients treated with
the shorter duration had higher rates of both local control (85
versus 73 percent, p = 0.01) and overall survival (59 versus 38
percent, p<0.001).

Novel schedules of fractionated
high-dose-rate and pulsed-dose-rate brachytherapy, which
simulate classical continuous low-dose brachytherapy, have been
developed and used with some success in patients with squamous
cell carcinoma of the soft palate and tonsillar fossa. In one
study of patients with predominantly T2 and T3 lesions at these
sites, the local relapse-free survival was approximately 90
percent, exceeding the value of 61 percent in historical
controls treated with EBRT

Cancer of the Soft Palate

Stage

Conventional
XRT

Hyperfractionated
XRT

T1

81 - 100%

100%

T2

65 - 88%

100%

T3

45 - 77%

60%

T4

25 - 35%

Control of Neck Nodes: N0 (97%) and N1-N3 (88%)

Squamous cell carcinomas of the soft palate
treated with radiation therapy alone or followed by planned neck dissection

The present study presents the experience at the University
of Florida with treatment of unselected patients with carcinomas of the soft
palate with radiation therapy (RT) alone or followed by planned neck dissection.RT doses delivered with megavoltage equipment ranged from 45 to 80
Gy (median 62.4) at 1.5 to 2.7 Gy (median 2) per fraction for patients treated with
once-daily fractionation and from 50.4 to 81.6 Gy (median 76.8) at
1.2 Gy per fraction for patients treated with twice-daily fractionation. Local
control rates at 5 years were 86% for T1, 91% for T2, 67% for T3, and 36%
for T4 carcinomas.Nodal control rates at 5 years
were 86% for N0, 76% for N1, 61% for N2, and 67% for N3 carcinomas. Overall treatment time
and planned neck dissection significantly affected nodal control in multivariate analysis.
Ultimate local-regional control rates at 5 years were 90% for
Stage I, 92% for Stage II, 84% for Stage III, and 60% for Stage IV disease.
Overall treatment time and planned neck dissection significantly affected ultimate
local-regional control in multivariate analysis. The overall survival rate at 5 years was
42% for all patients. The cause-specific survival rate at 5 years was 70% for all
patients. Overall treatment time and planned neck dissection significantly
affectedcause-specific survival in multivariate analysis. Conclusion: For limited carcinomas of the soft palate, RT (alone or
followed by planned neck dissection) results in relatively high local-regional controland
survival rates. For advanced carcinomas of the soft palate, local-regional control and
survival rates are relatively low and local-regional recurrence rates are substantial.
Advanced carcinomas of the soft palate may be better treated with RT and concomitant
chemotherapy.Discussion: At the University of Florida, the
policy is to treat almost all patients with squamous cell carcinomas of the oropharynx
with RT alone or followed by planned neck dissection for patients with clinically involved
cervical lymph nodes, reserving surgery for salvage treatment of patients with persistent
or recurrent disease after initial treatment
External beam RT for carcinomas of the soft palate is often delivered with megavoltage
equipment using parallel-opposed lateral portals treating the soft palate and upper
cervical lymph nodes and en face anterior portals treating lower cervical and
supraclavicular lymph nodes, shielding the hypopharynx, larynx, and spinal cord. For
limited carcinomas of the soft palate, external beam RT delivered with orthovoltage
equipment or electrons from megavoltage equipment using intraoral cones may precede
external beam RT delivered with megavoltage equipment Limited carcinomas of the soft
palate may also be treated with external beam RT followed by interstitial brachytherapy
using the guide gutter technique or the plastic tube technique Intraoral
cones and interstitial brachytherapy enable delivery of RT to the soft palate while
sparing the mandible and salivary glands. For limited carcinomas
of the soft palate, RT is associated with relatively high local-regional control and
survival rates and satisfactory functional outcome. Local control rates range from 83% to
96% for T1 carcinomas and from 67% to 81% for T2 carcinomas for external beam RT alone and
from 85% to 95% for T1 and T2 carcinomas for external beam RT followed by interstitial
brachytherapy.Cause-specific survival rates at 5 years for T1 and T2
carcinomas range from 67% to 84% for external beam RT alone and from 64% to 71% for
external beam RT followed by interstitial brachytherapy In the
present study, local control rates (86% and 91%, respectively) and cause-specific survival
rates (75% and 83%, respectively) at 5 years for T1 and T2 carcinomas are similar to those
reported by other institutions, if not somewhat better.

For advanced squamous cell carcinomas of the oropharynx, local-regional control and
survival rates are relatively low, and local-regional recurrence rates are substantial
after RT alone for advanced carcinomas of the soft palate. Local control rates range from
55% to 63% for T3 carcinomas and from 24% to 37% for T4 carcinomas. Cause-specific
survival rates at 5 years for T3 and T4 carcinomas range from 25% to 40% for RT In the present study, local control rates (67% and 36%, respectively)
and cause-specific survival rates (60% and 25%, respectively) at 5 years for T3 and T4
carcinomas are somewhat better than those reported by other institutions. For advanced
carcinomas of the oropharynx, altered fractionation schemes and chemotherapy in
combination with RT are promising approaches in attempt to improve local-regional control
and survival rates. Improved local-regional control and survival rates are reported for
accelerated fractionation schemes and hyperfractionation schemes compared with
conventional fractionation schemes. Induction chemotherapy followed by RT is not
correlated with improved local-regional control and survival rates when compared to RT
aloneRT and concomitant chemotherapy, on the contrary, are
associated with improved local-regional control and survival rates when compared with RT
alone.

Because the risk of subclinical disease in the clinically negative
neck is relatively high, even for early-stage primary cancers, elective neck RT is
indicated in all patients Patients with relatively low-volume positive neck
nodes that regress completely after RT are observed. Patients with high-volume N2 and N3
neck disease usually undergo a planned neck dissection after RT. Although recent data
suggest that the risk of isolated recurrences in the neck is relatively low for patients
with N2N3 neck disease who have a complete response to RT, our policy has generally
been to add the neck dissection, because of the low probability of successful salvage and
the improvement in cause-specific survival observed in the subset of patients who undergo
the operation.

A total of 24 patients with squamous cell carcinoma of the soft palate were treated at
the Veterans Administration Medical Center Minneapolis, MN, between February 1977 and May
1992. Of the 24 patients 2 had T1, 19 T2, 1 T3, and 2 had T4 lesions. Nineteen patients
did not have clinical nodal disease, stage (N0), 1 had N1, 2 N2, and 2 N3 disease (Table
1). All the patients were treated by 4 MeV linear accelerator. A 1.75 Gy median dose was
administered per fraction to a total of 70 Gy median dose.
Bilateral opposed compensated shrinking fields technique was used. RESULTS: The 3-year
disease free survival rate after external beam radiation therapy was
100%
(1 out of 1), 64.7% (11 out of 17), 100% (1 out of 1), and 0%, for patients with T1, T2,
T3, and T4 disease, respectively. Salvage surgery for recurrent disease was
successful in 57.1% (4 out of 7 patients (Table 2). The ultimate 3-year disease free
survival rate for the entire group, including surgical salvage, was 81% (17 out of 21)
(Fig 1). CONCLUSION: Radiation therapy alone in our institution resulted in tumor control
and survival rates compare favorably to previously published reports in the literature.
Surgery can be reserved as salvage procedure.

Results of irradiation in squamous cell carcinoma of the soft palate and uvula.

Out of a series of 235 patients presenting with tumours of the soft palate at the
Institut Curie, between 1958 and 1980, 146 cases were analysed to evaluate the results of
radical radiation therapy. Seventy patients (48%) had advanced T3-T4 disease and 40
patients (27%) had clinically involved metastatic nodes. All patients had a minimum
follow-up of 5 years. In 103 cases, megavoltage X-ray therapy was employed. For 43
patients, presenting with small or moderately advanced tumours, a combination of
megavoltage and intra-oral orthovoltage X-rays was used. The local control rate at 3 years
was 92% for T1, 70% for T2, 58% for T3 and 49% for T4 lesions. Nodal failure was seen in 19 patients. In 9 of these, it was not
associated with failure at the primary site, 7 out of 9 occurring marginally or outside
the treatment portals. Complications were observed in 16 patients, 7 requiring surgery.
The crude 3 and 5 year survival rate was 52 and 40%, respectively, and the disease-free
survival 59 and 53%.

Primary radiation therapy in the treatment of squamous cell carcinoma of the soft
palate.

Department of Radiation Oncology, School of Medicine, University of California Los
Angeles.

From 1970 to 1986, 45 patients received primary radiation therapy for squamous cell
carcinoma of the soft palate at the University of California Los Angeles (UCLA) Center for
the Health Sciences and Wadsworth Veteran's Administration Hospital. Seven patients were
lost to follow-up or had prior irradiation, and were excluded. Thirty-eight patients
received a median dose of 70 Gy (62.5 to 80 Gy) to the primary site. After a median
follow-up of 48 months, initial control of disease at the primary site was accomplished in
74% of the patients. The initial control by stage was as follows:
TI, 83%, T2, 67%; and T3, 63%. After surgical salvage, local control increased to 92%, 80%
and 75% for stages T1, T2, and T3, respectively. Twenty-nine percent (11 of 38)
of the patients had cervical node metastases at presentation. Radiation provided regional
control in 96% (26 of 27) with N0 disease and 86% (six of seven) with N1 disease at
diagnosis. Sixteen patients (42%) had an additional malignancy of the upper aerodigestive
tract. Because the incidence of second malignancies after treatment is high and surgical
salvage of treatment failures is possible, close follow-up is essential in the management
of this tumor. We conclude that radiation therapy is an effective modality for the
treatment of squamous cell carcinoma of the soft palate. Primary radiation therapy may
offer many patients the chance to avoid surgical procedures that are both cosmetically and
functionally debilitating without compromosing treatment outcome.

Carcinoma of the soft palate treated with irradiation: analysis of results and
complications.

This is an analysis of 75 patients with squamous cell carcinoma of the soft palate
and/or uvula treated with radical radiation therapy alone (64) or in conjunction with
planned neck dissection (11) between October 1964 and September 1983. All patients have a
minimum follow-up of 2 years and 60 (80%) have a minimum follow-up of 5 years. Patients
were excluded from analysis of disease control at the primary site and/or neck if they
died within 2 years of treatment with the site(s) continuously disease free. The initial local control rates and
ultimate local control rates after surgical salvage of irradiation failures
for patients treated with continuous-course irradiation were as follows: T1,
8/8 (100%) and 8/8 (100%); T2, 14/19 (74%) and 16/19 (84%); T3, 5/11 (45%)
and 5/11 (45%); and T4, 1/4 (25%) and 1/4 (25%). Overall,
7/55 patients (13%) treated with continuous-course irradiation experienced
irradiation-related bone or soft tissue complications; there was only one severe
complication. The 5-year determinate survival rates by modified AJCC stage for patients
treated with continuous-course irradiation are as follows: I, 83%; II, 78%; III, 38%; IVA,
0/2; and IVB, 25%

Primary radiation therapy in
the treatment of squamous cell carcinoma of the soft palate

From 1970 to 1986, 45 patients
received primary radiation therapy for squamous cell carcinoma of
the soft palate at the University of California Los Angeles (UCLA)
Center for the Health Sciences and Wadsworth Veteran' Administration
Hospital. Seven patients were lost to follow-up or had prior
irradiation, and were excluded. Thirty-eight patients received a
median dose of 70 Gy (62.5 to 80 Gy) to the primary site.
After a median follow-up of 48 months, initial control of disease at
the primary site was accomplished in 74% of the patients.

The initial control by stage
was as follows: T1, 83%; T2, 67%; and T3, 63%. After surgical
salvage, local control increased to 92%, 80%, and 75% for stages T1,
T2, and T3, respectively. Twenty-nine percent (11 of 38) of
the patients had cervical node metastases at presentation. Radiation
provided regional control in 96% (26 of 27) with NO disease and 86%
(six of seven) with N1 disease at diagnosis. Sixteen patients (42%)
had an additional malignancy of the upper aerodigestive tract.
Because the incidence of second malignancies after treatment is high
and surgical salvage of treatment failures is possible, close
follow-up is essential in the management of this tumor. We conclude
that radiation therapy is an effective modality for the treatment of
squamous cell carcinoma of the soft palate. Primary radiation
therapy may offer many patients the chance to avoid surgical
procedures that are both cosmetically and functionally debilitating
without compromising treatment outcome.